Shingo Tsukino was Usagi Tsukino's little brother in all versions of the series. He liked to tease Usagi and call her "Usagi the idiot," but Usagi cared for him deeply.

Shingo liked to play pranks on his sister, such as the time Usagi was worrying about her weight and he rigged the scale to break when she stood on it. Shingo also got along well with Chibiusa, and both of them took pleasure in teasing Usagi over her poor test results and clumsiness.

Shingo attended Juuban Municipal Primary School and had much better grades than his older sister. He loved to play video games, and was also a big fan of Sailor Moon and Sailor V, but did not know their identities. In the anime, he had a fear of cats, which caused him to initially dislike the fact that Luna came to live in the Tsukino home, but he eventually overcame his fear.

In the anime, he was friends with Mika Kayama, a little girl who went to his school and made dolls, and he also had a brief crush on Ami.